1,1-disubstituted alkene compounds find use in a number of applications such as adhesives, coatings, composites and the like. 1,1-disubstituted alkene compounds, with two ester substituents on the alkene double bond, are commonly known as methylene malonates. These compounds have been known since the 19th century and in the mid-20th century a number of researchers worked with these compounds, see D'Alelio U.S. Pat. No. 2,330,033; Coover U.S. Pat. No. 3,221,745 and U.S. Pat. No. 3,523,097; Halpern U.S. Pat. No. 3,197,318; and Ponticello U.S. Pat. No. 4,056,543 and U.S. Pat. No. 4,160,864, all incorporated herein by reference in their entirety for all purposes. Despite this work the 1,1-disubstituted alkene compounds have not been commercialized. The disclosed processes for the preparation of these compounds produce a number of by-products that negatively impact the stability of the desired products which precludes the reasonable use of the compounds. In addition, some of the by-products and starting materials are difficult to separate from the desired compounds. 1,1-disubstituted alkene compounds polymerize rapidly at room temperature under mild conditions in presence of nucleophilic or basic initiating species, which render them both useful, as well as, present problems with their stability. The problems with the processes and the products of the processes were not fully appreciated until Malofsky et al. studied the compounds and processes and developed ways to produce these compounds without the presence of starting materials and by-products that negatively impact their stability. Malofsky et. al. developed methods for enhancing the stability of such compounds while facilitating cure of the compounds at room temperature upon demand, see Malofsky et al. U.S. Pat. No. 8,609,885; U.S. Pat. No. 8,884,405; US2014/0329980; and US 2015/0073110; all incorporated herein by reference in their entirety for all purposes.
The work of Malofsky et al. resulted in commercial interest in 1,1-disubstituted alkene compounds for use in a variety of applications. For many uses the 1,1-disubstituted alkene compounds prepared in the Malofsky et al. patents and applications provide advantageous properties. Many of the 1,1-disubstituted alkene compounds prepared in the Malofsky et al. patents and applications exhibit glass transition temperatures near or below room temperature. Although the low glass transition temperatures are advantageous for a number of applications, to broaden the application scope for these compounds it is desirable to develop 1,1-disubstituted alkene compounds and compositions that can prepare polymers with higher glass transition temperatures.
Thus, what is needed are 1,1-disubstituted alkene compounds that are capable of forming polymers with glass transition temperatures of 60° C., more preferably above 80° C., even more preferably above 100° C. and even more preferably above 120° C. What are also needed are methods for enhancing the glass transition temperatures of polymers prepared from 1,1-disubstituted alkene compounds.